Research On Prediction Methods For Flow Boiling Heat Transfer In Channels

The saturated flow boiling heat transfer in channels has been widely used in many areas,such as energy engineering,chemical engineering,refrigeration engineering and aerospace engineering.However,due to its complicated internal mechanism,the flow boiling heat transfer models used in engineering still have many problems,such as too much limitations and low accuracy.Based on this,the main content of this paper is the research on prediction methods for saturated flow boiling heat transfer in channels and the main aim is to achieve a more precise model to predict flow boiling heat transfer coefficients so as to avoid under-design or over-design of related equipments and provide reference material for the design and application of heat-exchange equipments.43 existing flow boiling heat transfer correlations are collected and sorted out and an experimental database for development is established which consists of 17778 data points from 100 sources and 13 different fluids.Based on this database,the existing correlations are assessed and analyzed.After that,through combining fitting algorithm and theoretical analysis,a new general correlation for heat transfer coefficients is developed,achieving a mean absolute deviation(MAD)of only 3.7% against the database which is far below those existing correlations.In order to verify the accuracy,the new correlation is validated on the base of the experimental database for verification consisting of 10932 data points from 67 sources and 20 different fluids.The results prove its high prediction accuracy.Then all of the correlations are assessed together based on overall database to guide the selection of correlations in practical use.In the end,an evaporator design desktop application is developed which is mixed programmed by C# and Matlab.It is used to understand the impact of the selection of correlations to evaporator design through comparing the results of designs with different heat transfer correlations.